Re: Monitor calibration software/hardware
Re: Monitor calibration software/hardware
- Subject: Re: Monitor calibration software/hardware
- From: "Mark Segal" <email@hidden>
- Date: Fri, 21 Sep 2007 21:27:45 -0400
Derrick,
I'm running low luminance - 110cd. This is essential because I print on matte paper which is less reflective and has lower DMax than luster or glossy paper. The major matching issue for me (and perhaps other readers are also in the same boat) has ALWAYS been the luminosity range and shadow detail - not the colours. I find this combination of D65 and 110cd works quite well at simulating (under soft-proof with Paper White selected) what Epson Enhanced Matte will yield - recall this paper has an OBA which enhances "whiteness". I suspect that if I were to print on a matte paper that has no OBAs and therefore a more creamy appearance, D50 may be a more accurate forecaster of outcomes.
Cheers,
Mark
----- Original Message -----
From: Derrick Brown
To: MARK SEGAL
Cc: email@hidden
Sent: Friday, September 21, 2007 9:17 PM
Subject: Re: Monitor calibration software/hardware
Hi Mark,
There is one point here in particular that interests me - a purely technical one. Derrick, you may recall that some time back when you and Jack made a presentation on colour management here in Toronto there was discussion of the appropriate white point to select for monitor calibration. This was in the context of "WYSIWYG" between the soft-proof on the display and the print, all due allowances made for the difference between transmitted and reflected light etc. I distinctly remember the gist of the discussion being that while one could logically think a D50 white point would correlate properly with a D50 light source for viewing the prints, given how we humans see, such is not the case; rather we get a better display to print match with the display at D65 and the print viewing light source at D50. It had something to do with D50 on a display looking too yellow and dull relative to D50 lighting. Indeed, I find this to be the case in my set-up, where the room is dim unless I turn on the D50 lighting for viewing results. So my questions here: has the passage of time and new information revised this wisdom?
Some time ago, especially as CRTs were aged, their respective brightnesses were on the decline. As a result maintaining the D50 calibration with sufficient luminance became impossible. There was just no longer enough blue to maintain both color temperature and at the same time enough brightness. And you were likely using all the signal the red gun had.
In cases like this especially, it was a much better idea to calibrate to D65 because at least you now had some extra luminance.
I would also agree that the D65 whitepoint may yield a better calibration on a display with out DDC controls since its likely closer to the native white of the LCD. In the case of your 321, depending on the 10 or 12 bit version I think your native white was closer to 5700k.
Now, let me ask two supplementaries on the cyan/green issue Derrick mentions below. When I run ColorEyes Validation, the software generates 14 extra patches, of which according to the read-out produced, 11 are shades of grey and the other three are R, G and B at level 255 each. Usually, my validation shows insignificant Delta-E for those three primaries - most of the DE occurs in the grey readings. So with this kind of result, two questions: (1) where does Cyan come into the picture (OK it's green and blue but not measured as "Cyan", and (2) when I'm getting DE of 0.07 for these primaries, what possible difference would it make whether I calibrated my display (in this case a LaCie 321) at D50 or D65?
if you look deeper into the validation tool, there is an item called "evaluate display profile". Inside this you will see a set of reference files.
note the GMB macbeth. select it.
sun a validation. note the errors.
make two different calibrations. one d50, and one d65. i mention this because the macbeth was developed to be viewed at d50.
so once you run these to profiles then evaluate, you will notice less errors in the rich colors thru the d50 profile than that of the d65 profile. Now this also depends on the nature of your display, if its a relatively new ddc LCD (yours is) I would expect the D50 to yield you a closer match, if your booth is 5000k. What luminance are you running? is that possibly influencing the display match to the viewer?
thanks!
Derrick Brown
Integrated Color Corporation
81 Rogers Street
N. Billerica, MA 01862
tel: 978-670-1416
email@hidden
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